A zeolite crystal has small holes of about a molecular size in the crystal, and has a molecular sieve property selectively passing a molecule according to a size and a shape of the molecule of the zeolite. The zeolite is applied to a gas separation membrane, and a field of a reverse gasification permeability separation, a reverse osmosis separation, a gas sensor, and the like by utilizing the molecular sieve property. Above all, at present, there is paid attention to utilizing the zeolite membrane as a separation membrane separating an organic solvent or the like from the mixed solution of water, organic solvent, and the like.
As a module for separating the organic solvent by the separation membrane using the zeolite, for example, there is a module in which only the water content is passed through the membrane, and the organic solvent and the like are separated from the mixed solution of water, organic solvent, and the like, by installing a plurality of tubular separation membranes in which a zeolite membrane is deposited on a surface of a tubular support body and flowing the mixed solution of water and organic material through an outer side of the tubular separation membrane.
Further, there has been known a separation membrane module in which, by setting an outer tube so as to surround the tubular separation membrane with a distance around the tubular separation membrane, and flowing the mixed solution of water and organic solvent through between the tubular separation membrane and the outer tube, the mixed solution passes at a high speed in the vicinity of the tubular separation membrane and is circulated around a whole of the tubular separation membrane with a turbulent flow, whereby separation efficiency is improved (refer to, for example, Patent Document 1).
In the separation membrane module mentioned above, a certain degree of effect of improving the separation efficiency can be recognized, however, the mixed solution has only a little chance of flowing between the tubular separation membrane and the outer tube, and it cannot be said to be sufficient in the case of further increasing separation performance.
On the other hand, in the separation membrane module described above, as a structure for intending to solve a further problem by paying attention to a view point of a strength of the separation membrane in addition to the problem of intending to improve the separation efficiency, there has been known the plurality of tubular separation membranes installed side by side, each structured such that a closed end is formed as a free end, an open end is formed as a fixed end, a tube end part having a screw portion is attached to an outer periphery of the fixed end, and the tube end part is screwed with a tube plate so as to be supported in a cantilever manner (refer to, for example, Patent Document 2).
In the separation membrane module, since the mixed solution of water and organic material flows in a direction which is orthogonal to the tubular separation membrane, a stress is applied to the tubular separation membrane, an extra load is applied to the tubular separation membrane, a seal portion of a joint between the tubular separation membrane and the tube end part, or the like, and there is a possibility that the tubular separation membranes occur a tube vibration, resulting in such problems that a crack is occurred in the tubular separation membrane or a breakage of the seal portion is occurred.
Patent Document 1: WO2004/035182
Patent Document 2: Japanese Unexamined Patent Publication